Rumored
to have been prescribed by the Incas to treat serious ailments, the herb pau
d'arco has recently been investigated as a remedy for infectious diseases
and cancer. Though its anticancer properties are debatable, it may indeed
combat a variety of infections.

Treats vaginal yeast infections.

Helps get rid of warts.

Reduces inflammation of the airways in bronchitis.

May be useful in treating such immune-related disorders as asthma,
eczema, psoriasis, and bacterial and viral infections

What Is Pau d'arco?

Pau d'arco is obtained from the inner bark of a tree -- Tabebuia impetiginosa -- indigenous to the rain forests of South America. Native tribes have taken advantage of its healing powers for centuries. Pau d'arco is also known as lapacho, taheebo, or ipe roxo. In the United States, however, it's always sold as pau d'arco.

The therapeutic ingredients in pau d'arco include a host of potent plant chemicals called naphthoquinones. Of these, lapachol has been the most intensely studied.

How Does Pau d'arco Work?

Lapachol and other compounds in pau d'arco help destroy the microorganisms that cause diseases and infections, ranging from malaria and the flu to yeast infections. Most people, however, are interested in the potential cancer-fighting properties of this herb.

Major benefits: Pau d'arco appears to combat bacteria, viruses, and fungi; reduce inflammation; and support the immune system. One of its best-documented uses is for vaginal yeast infections; herbalists often recommend a pau d'arco tea douche to restore the normal environment of the vagina. In capsule, tablet, tincture, or tea form, pau d'arco may be effective in strengthening immunity in people with chronic fatigue syndrome, HIV or AIDS, or chronic bronchitis. The herb's anti-inflammatory properties likewise benefit acute bronchitis, which involves inflammation of the respiratory passages, as well as muscle pain. And a tincture of pau d'arco applied directly to warts is useful in eradicating them.

Additional benefits: Pau d'arco's anticancer activity is subject to continuing debate. Because of the herb's traditional reputation as a cancer fighter, the National Cancer Institute (NCI) investigated it, identifying lapachol as its most active ingredient. In animal studies, pau d'arco showed promise in shrinking tumors, and so the NCI began human trials using high doses of lapachol in the 1970s. Again, there was some evidence that lapachol was active in destroying cancer cells, but participants taking a therapeutic dose suffered serious side effects, including nausea, vomiting, and blood-clotting problems. As a result, research into lapachol and its source, pau d'arco, was abandoned.

Critics of this investigation believe that using therapeutic doses of pau d'arco -- and not simply the isolated compound lapachol -- would have produced similar benefits without the potentially dangerous blood-thinning effects. It's likely that lapachol interferes with the action of vitamin K, needed for the blood to clot properly. Some researchers suggest that other compounds in pau d'arco supply some vitamin K, so that use of the whole herb would not interfere with blood clotting. Others think that combining lapachol with vitamin K supplements might make it possible for people to take doses of lapachol high enough to permit its potential antitumor action to be further studied without provoking a reaction. Despite the controversy, many practitioners rely on the historical evidence of pau d'arco's anticancer action and often recommend it as a complement to conventional cancer treatment.

Dosage: When using pau d'arco in capsule or tablet form, the typical daily dosage is 250 mg twice a day. This dose of pau d'arco is often recommended for chronic fatigue syndrome or HIV and AIDS in alternation with other immune-boosting herbs such as echinacea or goldenseal. Pau d'arco is also commonly consumed as a tea in dried herb form. To make it, steep 2 or 3 teaspoons of pau d'arco in two cups of very hot water; drink the tea over the course of a day.

Guidelines for use: Herbalists recommend whole-bark products (not only those that contain just lapachol) because they suspect the herb's healing properties come from the full range of plant chemicals in the bark. For vaginal yeast infections: Let pau d'arco tea cool to lukewarm before using it as a douche. For warts: Apply a tincture-soaked compress to the affected area at bedtime and leave it on all night. Repeat until the wart disappears.

Possible Side Effects

Whole-bark products are generally safe; they do not produce the side effects of high doses of lapachol. If pau d'arco tea or supplements cause stomach upset, take them with food.